Process for separating minerals by flotation



.such complex operations practicable.

Patented Feb. 26, 1 946 2,395,639 I raocass FOR snrana'rrnc am s BYrLo'ra'rroN Louis 'il. Morison, Alhambra, and Orson Sutler Shepard,lPalo Alto, Caliifl, assignors to Petrolite Corporation, Ltd, acorporation of Delaware No Drawing. Application April 20, 1943, SerialNo. 483,792

Claims.

This invention relates to separating minerals by froth flotation, andparticularly to separating metallic minerals. 1

One object of our invention is to provide a novel process for separatingminerals or ores into their more valuable and their less valuablecomonents, by means of a froth flotation operation.

Another object of our invention is to beneficiate ores, particularly ofmetallic minerals, by apsuch finely ground ore, which mass or pulpusually contains a major proportion of water and only a. minorproportion of finely-ground ore;

subject such pulp to the action of a highly speciflc chemical reagent ina flotation machine or flotation cell, in the presence of a large amountof air; and recover the valuable constituents of the ore from themineralized froth which overflows from the flotation cell. Manyvariations of this basic procedure have been developed, including theuse of different types of flotation cells, different procedures ofcombining individual operations into different flow sheets to floatsue.-

components, etc. The chemical side of the operation has likewise beenvaried greatly to make In addition to reagents adapted to collect theore values in the froth (collectors), other reagents for improving thefrothing characteristics of the flotation operation (frothers) or forselectively improving or retarding the flotation of individual membersamong the valuable components of the ore (activators or depressors) havebeen developed. The characteristics of the chemical reagents that havebeen used in the flotation operation differ greatly, until it may besaid that a reagents flotation possibilities may best be determined byactual test in the process.

The process which we have discovered and which we believe to be novelcomprises the" use of a reagent of a unique type-in a flotation processfor the recovery of valuable constituents of minerals or ores. ,Ourreagent comprises broadly a mixture of a blown fatty oil and a petroleumbody. In some instances, we have found, the

blown fatty oil in such mixture may be profitably replaced in part by asulfonated fatty body of a particular type, th improvement in resultsbeing so great as almost to constitute a separate invention.

Blown fatty oils, and particularly blown castor oil, have long beenknown and have been used in various arts, including the demulsiflcationof petroleum oils. In general, they are produced by the action, on afatty oil or fatty acid, of an oxygen-containing gas, commonly air, andusually at somewhat elevated temperatures. In characteristics, theyrange from relatively low-vise cosity, light-colored liquids to nearlyblack liquids whose consistency may best be defined as semi-- livery. Weprefer to use blown castor oil as the preferred ingredient of this typein our reagent.

We have found that variations in the nature of the blown fatty oilaffect the results to some degree. We prefer to employ a blown oil ofthe drastically oxidized typ similar to that de scribed in U. S. PatentNo. 2,023,979 to C. N. Stehr, in producing our reagent. But we havefound broadly that mixtures comprising blown fatty oils and petroleumbodies, and mixtures comprising suchcomponents plus a sulfonated fattybody y of the kind described below, are valuable flotacessively andseparately at number of valuable tion reagents; We prefer to use theblown fatty oil and the petroleum body comprising our reagent inproportions of 1:4 and 4:1. In some instances, the best results havebeen obtained by the use of reagents comprising substantially equalproportions of such two ingredients.. On the other hand, mixtures in theproportions of 1:9 or 9:1 have sometimes been most useful. Where asulfonated fatty body of the kind described below is used to replace apart of the blown fatty oil, the above recited proportions still apply,the proportion then being taken betwen the petroleum body and the sum ofthe fatty bodies.

It has long been known that various animal, vegetable, and marine 'oilscan be blown or oxidized, so as to yield materials which difier inchemical and physical properties and characteriswerejderifve dl Theoxidation process is generally conducted by means of moist or dry air,ozone,

ozonized air, or a mixture of the same. It may be conducted atatmospheric pressure, or may ate, or may consist of organic material,such as alpha pinene or the like. Oxidation may be conducted in arelatively short time, such as 20 hours, or may require 200 hoursormore.

Patents which describe conventional blown oils or conventional methodsof making various blown oils for various purposes include the following:U. S. Patent No. 1,929,399, dated October 3, 1933, to Fuchs; U. S.Patent No. 1,969,387, dated August '7, 1934, to Tumbler; U. S. PatentNo. 2,023,979, dated December 10, 1935, to Stehr; U. S. Patent No.2,041,729, dated May 26, 1936,. to Seymour; and U. S. Patent No.1,984,633, dated December 18, 1934, to De Groote and Keiser.

Insofar that the material or composition we prefer to use as a,component of the flotation agent of our process is derived from blowncastor 011, an effort will be made to describe said material or compoundin considerable detail. Mild oxidation of castor oil (see "ChemicalTechnology and Analysis Of Oils, Fats and Waxes, by Lewkowitsch, 6thedition, vol. 2, p. 406) produces relativelysmall modiflcationsincertain important chemical indices, such as the iodine value, the acetylvalue, and the saponification value. If drastic oxidation takes place,"either b continued mild oxidation from the: very beginning of thereaction, or as induced by either a higher temperature of reaction, orby the presence of a catalyst, such. as alpha plnene, manganesericinoleate, etc., then one obtains an oxidized oil havingcharacteristics which clearly indicate that drastic oxidation ha takenplace. These indices of drastic oxidation are a. relatively low iodinevalue, such as 65 or less, which may be as low as 40 or thereabouts; anacetyl valuecf approximately 160 to 200; an increased viscosity; aspecific gravity of almost 1, or even a trifle over 1 at times; and inabsence of other coloring matte a deep orange to deep brown color.

Drastically oxidized castor oil can be prepared by well known methods,or such products can be purchased on the open market under various tradenames, such as blown castor oil," "bodied by direct oxidation of thevarious fats and oils,

but also by direct oxidation of the fatty acids.

to Hinrichs. Reference is also made to polymerized castor oil or'similaroils of the kind disclosed in U. S. Patent No. 2,114,651, dated April19, 1938, of Ivor M. Colbeth. It might also be desirable to point outthat the expression blown oil," as herein used, contemplates blownunsaturated liquid waxes, such as blown sperm oil. -It is understoodthat lnthe appended claims the expression blown fatty oil" is used inits broad sense to include all the various materials, such as esterifledblown fatty acids.

- A drastically oxidized castor oil of the above kind may, for example,have approximately the following characteristics:

Acid number 13.2 to 25.0 Saponiflcation number 230.5 to 274.0 Iodinenumber 43.5 to 55.0 Acetyl number 164.0 to 192.0 Hydroxyl value 188.0 to220.0 Percent unsaponifiable matter.. 1.1 Percent nitrogen 0.0 Percentso: 0.0 Percent ash Trace Another variety of drastically oxidized castorlt is our preference to use blown oils, rather than blown fatty acids.We particularly prefer to use blown vegetable oils, such as blowncottonseed oil. .blown corn oil, blown soyabean oil, blown rapeseed oil,and especially. blown castor oil. Cur

preferred blown oil is a blown castor oil, which has been blown somewhatmore drastically than indicated by the indices above recited. and whichhas been blown just short of the stage which produces semi-livery oils,as described in the aforementioned Stehr Patent No. 2,023,979.

The sulfonated fatty body which may comprise a component of our reagent,while obtained by the broad process of reacting sulfuric acid on a fattyacid or a fatty oil, is not an ordinary sulfonated oil. It is neutral orslightly alkaline to methyl orange indicator, which means that thecarboxyl group present is substantially un-neutralized, whereas ordinarysulfonated. fatty oils are neutralized in the carboxyl group to animportant degree, and are freely water-soluble becauseof their contentof salts of fatty acid residues. the ordinary commercial neutralizedtype to be distinctly unsuited for use in our process, as they tend'toreact with calcareous Emue minerals 'and float. such undesirablecomponents of the Blown ricinoleic acid may be derived in the mannotindicated in U. 8. Patent No. 2.034.941. dated I March 24, 1936. to DeGroote, Kaiser ond'wirtel. It should be noted that blown oils in thebroad generic sense herein employed include not only the productsderived by oxidation, but. also the products de'rivedby polymerization.Reference is madeto polymerized .ricinoleic acid described ores beingtreated. Our suifonated fatty oil contains only small amounts of water,commonly sulfcnated fatty oils are, in the free state, dibaaic acids,havin: a stroncly acidic hydrosen atom inU. S.P,at,cnt Ifo.'1.901,163,dated March 1.1933, 76' present in an acidic sulfate or sulfonic map, a

We have found sulfonated fatty oils of well as a weakly acidic hydrogenatom in the carboxyl group. I When such compounds are neutralized tomethyl orange indicator with any suitable base, like caustic soda,potassium hydroxide ammonia, or triethanolamine, or the'like, only thestrongly acidic hydrogen atom is replaced. Further addition of the baseresults in replacing the carboxylic hydrogen atom. The salts, when thesecompounds are neutralized only to methyl orange, are known as acidsalts. Our process contemplates the use of a mixture containing asulfonated fatty acid or sulfonated fatty oil, in

which the carboxyl group is not neutralized, in

contradistinction to neutral salts, except to the extent that theremight be a relatively slight over-neutralization. Sometimes the acidsalts of these compounds decompose in time, when neutralized withammonia, so that they may exhibit some acidity to methyl orange. Thisdoes not destroy the utility of the material as an ingredient in thereagent of our process but the acidity exhibited may result in anunfavorable corrosive action on metal surfaces with which the reagentcomes in contact. The sulfonated fatty acid or the sulfonated fatty oilwill also contain nonsulfo. fatty materials, as is well understood inthe art. The percentage of sulfur-containingacidic materials insulfonated fatty bodies varies widely. We prefer to employ only thosesulfonated fatty bodies that contain a minor proportion ofsulfurcontaining acidic materials, the sulfonated fatty ingredient ofour reagent usually producing at best, only a poor water dispersion whentested in absence of the other ingredients of the reagent. Organicallycombined sulfur trioxide preferably does not exceed 6% of the sulfonatedfatty matter on an anhydrous or active matter basis.

.The petroleum body included in our reagent may be selected as desired.In some instances. crude petroleum oil itself is satisfactory; in othercases, gas oil, kerosene, gasoline, or other distillate is to bepreferred. We prefer specifically to employ the petroleum distillatesold commercially as stove oil, as it appears'to have, in addition tohaving desirable properties as used in our reagent for floatingminerals, certain desirable physical properties, i. e., it is relativelystable and non-volatile, it is relatively limpid, and it is relativelynon-flammable; As an example of the specifications of such a stove oil,we give the following:

The flotation agent contemplated for use in our process is preparedby'simply mixing the blown fatty oil and the petroleum body, or theblown fatty oil, the sulfonated fatty body, and the petroleum body, inthe desired proportions. The reagent so compounded is used in theordinary operating procedure of the flotation process.

In some instances, the components of the mixture are compatible andcombine into a perfectly homogeneous liquid reagent. In other in--stances, they are more or less incompatible, and

. tend to separate or stratify into layers on quie s cent standing. Ininstances where the ingredients are capable of making a homogeneousmixture, the reagent may be handled and used without diiiflculty. Ifanon-homogeneous mixture results when the desired proportions areemployed, a number of expedients may be resorted to to obviate thedimculty. For example, since it is common to include the use of afrothing agent in many flotation operations, the collector whichcomprises our reagent may be homogenized by being combined with a mutualsolubilizer in the form of the desired frother, e. g., cresylic acid,pine oil, terpineol, one of the alcohols manufactured and used for frothpromotion, like the duPont alcohol frothers, etc. If such mutualsolubilizer is incorporated in or with the abover mechanically, as by abeater or agitator, im-

mediately before injecting it into the mineral pulp which is to betreated forthe recovery of we have employed with favorable results, werecite I the following, without being limited to the exact compositionsshown:

Example 1 Reagent X-354 is a mixture of 60 parts of a drasticallyoxidized castor oil of the kind described above and 40 parts of stoveoil.- This reagent, on a lead-zinc ore, behaved very much like potassiumethyl xanthate, which was highly effective on that ore. The froth, usingreagent X-354, looked clean and was heavily laden with galena, in thelead flotation run. The froth was similar to that obtained using thexanthate reagent; and X-354 appeared equally powerful on thefreshly-ground ore sample. Because of its lower cost, reagent X-354would have an economic advantage over the higher-priced xanthatereagent.

Example 2 A reagent was prepared fromdrastically oxidized castor oil,sulfonated castor oil neutralized just to the methyl orange end-point.and stove oil, the proportions of, blown oil, sulfonated oil, and stoveoil being approximately 5:4:11. This reagent was homogenized by theaddition of secondary butyl alcohol, using 1.5 parts of the alcohol for20 parts of the above mixture. The homo geneous reagent so prepared wasused in floating a lead-zinc ore from Broken Hill, Australia. This orealso contained quartz, calcite and chalcopyrite, and is typical of areasonably dimcult lead-zinc ore. The above reagent gave a much highergrade lead concentrate than did potassium ethyl xanthate, and neariy ashigh an economic lead recovery. It floated .very little gangue, the

' aleno appearance.

was used, was not quite so clean; and the froth,

mineral-bearing froth having a clean, metallic The froth, when xanthatewhen a water-soluble neutralized sulfonated castor oil was used, wasdefinitely not as clean as in the other two cases. The neutralized sul=fonated castor oil gave definitely poor results on this ore, producing aviscous, slow-breaking dirty agent used in these runs floatschalcopyrite. The reagent was found to float sphalerite, activated bycopper sulfate, satisfactorily. It was found not to float clean pyritein the absence oi. copper sulfate.

. whereas potassium ethyl xanthate floats both copper sulfide andpyrite, unless a pyrite depressor is present in the cell. Thisdifi'erence bet" zen the experlmentalr'reagent and the xanthate is ofimp rtance in some copper flotation operations.

. Example 3 Reagent 'X-37l is a mixture of 1 part drastically oxidizedcastor oil of the kind described above and 9 parts stove oil, mixed withparts of terpineol, to incorporate the frother and collector A in asingle homogeneous reagent. This reagent,

when applied to a lead-zinc ore from Broken Hill, Australia, appeared tohave to an exceptional degree the property of collecting galena withoutcollecting SDhalerite, without adding a depressor to prevent theflotation of the zinc mineral.

Example 4 Reagent 2-372. is similar to the reagent recited under Example2 above, except that the blown oil-sulfonated oil-stove oil mixture(proportions, 5:4:11) was mixed with an equal weight of terpineol beforeuse. Reagent X-373 comprises a mixture of the blown oil, sulfonated oil,

A reagent was prepared from a drastically oxidized castor oil, asulfonated castor oil, -and a stove oil, of the kind described above,the proportion of blown oil, sulfonated oil and stove oil beingapproximately 7:3:10, and the stove oil containing about 20% of aromaticpetroleum bodies. This reagent was mixed with about 5% of secondarybutyl alcohol, and was used in such homogeneous admixture as a flotationreagent. It

was effective in recovering values from a Utah lead-zinc ore, whenapplied in the regular flotation procedure.

Theforegoing examples show the effectiveness of several examples of ourflotation agents which are materially diflerent' in percentagecomposition, yet all of which embrace the basic concept of ourinvention. These examples show that our reagents are eflective infloating galena, sphalerite, and chalcopyrite, respectively under properoperating conditions. They show that the reagent may contain apreponderance of blown oil and a minor proportion of sulfonated oil, orvice versa. They showthat the proportion of fatty materials topetroleumbody may be varied widely. They show that asuitable frothermaybe incorporated into the reagent to produce a single homogeneous reagentcombining the properties of collector and frother.

The operative steps employed in practicing our process are those of-theordinary flotation process as widely usedcommerclally today. However,for sake of example we have set forth below one "typical procedure,employing a lead-zinc ore,

without intending to be limited to that procedure.

' It is understood that various of the steps recited maybe modified,amplified or eliminated, as deasoaose sired, without departing from thespirit of this invention. The ore to be treated i first dryground tominus GE-mesh in-size, a screen analysis showing the following range ofsizes:

, Per cent I Plus mesh Trace 65-80 mesh 2 -100 mes 10 -150 mesh 18 -170mes 5 -200 mes 11 Minus 200 mesh 54 Total 100 erite was then activatedby the addition of copper sulfate, 1.2 lb./ton of ore, and arougher-cleaner operation was conducted to float the-zinc mineral, usingthe collector in the proportion of 0.02 lb./ton of ore in each cell. Insome of the runs, a zinc depressor, such as sodium cyanide or zincsulfate, or'both, was required to be used at the rate of a. fraction ofa pound per ton.

One distinct advantage that our reagents enjoy over the flotationreagents now in commercial use is that they are less expensive toproduce. Therefore, even in instances where they are not technically theequal of such reagents (on a pound-ior-pcund basis) it is frequentlydesirable to substitute them for suchmore expensive reagents. Theflotation agents of our invention may be used in conjunction with otherflotation reagents, e. g., xanthates, and do not destroy theireffectiveness. In some instances, it is desirable to use our flotationagents in the rougher cell operation and use the xanthate to recover thevalues in the cleaner cell. In other instances, the two reagents may beused in a single operation in a single cell.

We claim:

1. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector comprising a mixture ofa blown fatty oil and a petroleum body.

2. In a froth flotation process for the beneflciation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector comprising a mixture oia. blown fatty oil, a petroleum body. and a mutual sclubilizing agent.

3. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore,-and agitating andaerating the pulp in the presence of a collector comprising amechanically homogenized mixture of a blown fatty oil and a petroleumbody.

4. In afroth-flotation process for the beneficiation of metallic sulfideores, the steps of forming a pulp of the ore, and agitating and aeratingthe pulp in the presence of a collector comprising amechanicallyhomogenized mixture of a pulp in the presence of a collector comprisinga mixture of a blown vegetable oil, a petroleum body, and a mutualsolubilizing agent- 6. In a froth flotation process for thebeneficiation of metallic sulfide ores, the steps of forming a pulp ofthe ore, and agitating and aerating the pulp in the presence of amechanically homogenized mixture of a blown vegetable oil and a De-'pulp in the presence of a collector comprising a mixture of a blowncastor oil, a petroleum body, and a mutual solubilizing agent.

9. In a froth flotation proces for the beneficiation of metallic sulfideores, the steps of forming a pulp of the ore, and agitating and'aeratingthe pulp in the presence of a collector comprising a blown castor oiland a petroleum body.

10. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a, collector comprising a mixtureof a castor oil blown just short of the semi-livery state and apetroleum body.

11. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector comprising a mixture ofa castor oil blown just short of the semi-livery state, a petroleumbody, and a mutual solubilizing agent.

12. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector comprising amechanically homogenized mixture of a castor oil blown just short of thesemi-livery state'and a petroleum body.

13. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of'the ore, and agitating andaerating the pulp in the presence of a collector as recited in claim 1,the collector including a sulfonated fatty body which is substantiallyunneutralized in the carboxyl group. i

14. In a froth flotation-process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector as recited in claim 2,the collector including. a sulfonated fatty body which issubstantially'unneutralized in the carboxyl group.

15. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector a recited in claim 3,the collector including a sulfonated fatty body which is substantiallyunneutralized in the carboxyl group.

16. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector as recited in claim 7,the collector including a sulfonated castor oil which is substantiallyunneutralized in the carboxyl group.

17. In a, froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore', and agitating andaerating the Y pulp in the presence of a collector as recited in claim 8the collector including a sulfonated castor oil which is substantiallyunneutralized in thecarboxyl group.

19. In a froth flotation process for the beneficiation of metallicsulfide ores, the steps of forming a pulp of the ore, and agitating andaerating the pulp in the presence of a collector as recited in claim 10,the collector including a sulfonated castor oil which is substantiallyunneutralized in the carboxyl group.

20. In a froth flotation process for the beneflcia tion of metallicsulfide ores, the steps of forming apulp of the ore, and agitating andaerating the pulp in the presence of a collector as recited in claim 11,the collector including a sulfonated castor oil which is substantiallyunneutralized in the carboxyl group.

LOUIS T. MONSON. ORSON cum

